/* sha1sum.c - print SHA-1 Message-Digest Algorithm   
 * Copyright (C) 1998, 1999, 2000, 2001 Free Software Foundation, Inc.  
 * Copyright (C) 2004 g10 Code GmbH  
 *  
 * This program is free software; you can redistribute it and/or modify it  
 * under the terms of the GNU General Public License as published by the  
 * Free Software Foundation; either version 2, or (at your option) any  
 * later version.  
 *  
 * This program is distributed in the hope that it will be useful,  
 * but WITHOUT ANY WARRANTY; without even the implied warranty of  
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the  
 * GNU General Public License for more details.  
 *  
 * You should have received a copy of the GNU General Public License  
 * along with this program; if not, write to the Free Software Foundation,  
 * Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.  
 */  
  
  
#include <stdio.h>  
#include <stdlib.h>  
#include <string.h>  
#include <assert.h>  
#include <errno.h>  
#include "sha1.h"
  
  
/****************  
 * Rotate a 32 bit integer by n bytes  
 ****************/  
#if defined(__GNUC__) && defined(__i386__)  
static inline u32 rol( u32 x, int n)  
{  
    __asm__("roll %%cl,%0"  
            :"=r" (x)  
            :"0" (x),"c" (n));  
    return x;  
}  
#else 
// 循环左移
#define rol(x,n) ( ((x) << (n)) | ((x) >> (32-(n))) )  
#endif  
  
  
void sha1_init( SHA1_CONTEXT *hd )  
{  
    assert (sizeof (u32) == 4);  

    hd->h0 = 0x67452301;  
    hd->h1 = 0xefcdab89;  
    hd->h2 = 0x98badcfe;  
    hd->h3 = 0x10325476;  
    hd->h4 = 0xc3d2e1f0;  
    hd->nblocks = 0;  
    hd->count = 0;  
}  
  
  
/*  
 * Transform the message X which consists of 16 32-bit-words  
 */  
static void  
transform( SHA1_CONTEXT *hd, unsigned char *data )  
{  
    u32 a,b,c,d,e,tm;  
    u32 x[16];  
  
    /* get values from the chaining vars */  
    a = hd->h0;  
    b = hd->h1;  
    c = hd->h2;  
    d = hd->h3;  
    e = hd->h4;  
  
#ifdef BIG_ENDIAN_HOST  
    memcpy( x, data, 64 );  
#else  
    { int i;  
        unsigned char *p2;  
        for(i=0, p2=(unsigned char*)x; i < 16; i++, p2 += 4 ) {  
            p2[3] = *data++;  
            p2[2] = *data++;  
            p2[1] = *data++;  
            p2[0] = *data++;  
        }  
    }  
#endif  
  
  
#define K1  0x5A827999L  
#define K2  0x6ED9EBA1L  
#define K3  0x8F1BBCDCL  
#define K4  0xCA62C1D6L  
#define F1(x,y,z)   ( z ^ ( x & ( y ^ z ) ) )  
#define F2(x,y,z)   ( x ^ y ^ z )  
#define F3(x,y,z)   ( ( x & y ) | ( z & ( x | y ) ) )  
#define F4(x,y,z)   ( x ^ y ^ z )  
  
  
#define M(i) ( tm =   x[i&0x0f] ^ x[(i-14)&0x0f]    \
               ^ x[(i-8)&0x0f] ^ x[(i-3)&0x0f]      \
               , (x[i&0x0f] = rol(tm,1)) )  
  
#define R(a,b,c,d,e,f,k,m)  do { e += rol( a, 5 )   \
            + f( b, c, d )                          \
            + k                                     \
            + m;                                    \
        b = rol( b, 30 );                           \
    } while(0)  
    R( a, b, c, d, e, F1, K1, x[ 0] );  
    R( e, a, b, c, d, F1, K1, x[ 1] );  
    R( d, e, a, b, c, F1, K1, x[ 2] );  
    R( c, d, e, a, b, F1, K1, x[ 3] );  
    R( b, c, d, e, a, F1, K1, x[ 4] );  
    R( a, b, c, d, e, F1, K1, x[ 5] );  
    R( e, a, b, c, d, F1, K1, x[ 6] );  
    R( d, e, a, b, c, F1, K1, x[ 7] );  
    R( c, d, e, a, b, F1, K1, x[ 8] );  
    R( b, c, d, e, a, F1, K1, x[ 9] );  
    R( a, b, c, d, e, F1, K1, x[10] );  
    R( e, a, b, c, d, F1, K1, x[11] );  
    R( d, e, a, b, c, F1, K1, x[12] );  
    R( c, d, e, a, b, F1, K1, x[13] );  
    R( b, c, d, e, a, F1, K1, x[14] );  
    R( a, b, c, d, e, F1, K1, x[15] );  
    R( e, a, b, c, d, F1, K1, M(16) );  
    R( d, e, a, b, c, F1, K1, M(17) );  
    R( c, d, e, a, b, F1, K1, M(18) );  
    R( b, c, d, e, a, F1, K1, M(19) );  
    R( a, b, c, d, e, F2, K2, M(20) );  
    R( e, a, b, c, d, F2, K2, M(21) );  
    R( d, e, a, b, c, F2, K2, M(22) );  
    R( c, d, e, a, b, F2, K2, M(23) );  
    R( b, c, d, e, a, F2, K2, M(24) );  
    R( a, b, c, d, e, F2, K2, M(25) );  
    R( e, a, b, c, d, F2, K2, M(26) );  
    R( d, e, a, b, c, F2, K2, M(27) );  
    R( c, d, e, a, b, F2, K2, M(28) );  
    R( b, c, d, e, a, F2, K2, M(29) );  
    R( a, b, c, d, e, F2, K2, M(30) );  
    R( e, a, b, c, d, F2, K2, M(31) );  
    R( d, e, a, b, c, F2, K2, M(32) );  
    R( c, d, e, a, b, F2, K2, M(33) );  
    R( b, c, d, e, a, F2, K2, M(34) );  
    R( a, b, c, d, e, F2, K2, M(35) );  
    R( e, a, b, c, d, F2, K2, M(36) );  
    R( d, e, a, b, c, F2, K2, M(37) );  
    R( c, d, e, a, b, F2, K2, M(38) );  
    R( b, c, d, e, a, F2, K2, M(39) );  
    R( a, b, c, d, e, F3, K3, M(40) );  
    R( e, a, b, c, d, F3, K3, M(41) );  
    R( d, e, a, b, c, F3, K3, M(42) );  
    R( c, d, e, a, b, F3, K3, M(43) );  
    R( b, c, d, e, a, F3, K3, M(44) );  
    R( a, b, c, d, e, F3, K3, M(45) );  
    R( e, a, b, c, d, F3, K3, M(46) );  
    R( d, e, a, b, c, F3, K3, M(47) );  
    R( c, d, e, a, b, F3, K3, M(48) );  
    R( b, c, d, e, a, F3, K3, M(49) );  
    R( a, b, c, d, e, F3, K3, M(50) );  
    R( e, a, b, c, d, F3, K3, M(51) );  
    R( d, e, a, b, c, F3, K3, M(52) );  
    R( c, d, e, a, b, F3, K3, M(53) );  
    R( b, c, d, e, a, F3, K3, M(54) );  
    R( a, b, c, d, e, F3, K3, M(55) );  
    R( e, a, b, c, d, F3, K3, M(56) );  
    R( d, e, a, b, c, F3, K3, M(57) );  
    R( c, d, e, a, b, F3, K3, M(58) );  
    R( b, c, d, e, a, F3, K3, M(59) );  
    R( a, b, c, d, e, F4, K4, M(60) );  
    R( e, a, b, c, d, F4, K4, M(61) );  
    R( d, e, a, b, c, F4, K4, M(62) );  
    R( c, d, e, a, b, F4, K4, M(63) );  
    R( b, c, d, e, a, F4, K4, M(64) );  
    R( a, b, c, d, e, F4, K4, M(65) );  
    R( e, a, b, c, d, F4, K4, M(66) );  
    R( d, e, a, b, c, F4, K4, M(67) );  
    R( c, d, e, a, b, F4, K4, M(68) );  
    R( b, c, d, e, a, F4, K4, M(69) );  
    R( a, b, c, d, e, F4, K4, M(70) );  
    R( e, a, b, c, d, F4, K4, M(71) );  
    R( d, e, a, b, c, F4, K4, M(72) );  
    R( c, d, e, a, b, F4, K4, M(73) );  
    R( b, c, d, e, a, F4, K4, M(74) );  
    R( a, b, c, d, e, F4, K4, M(75) );  
    R( e, a, b, c, d, F4, K4, M(76) );  
    R( d, e, a, b, c, F4, K4, M(77) );  
    R( c, d, e, a, b, F4, K4, M(78) );  
    R( b, c, d, e, a, F4, K4, M(79) );  
  
    /* Update chaining vars */  
    hd->h0 += a;  
    hd->h1 += b;  
    hd->h2 += c;  
    hd->h3 += d;  
    hd->h4 += e;  
}  
  
  
/* Update the message digest with the contents  
 * of INBUF with length INLEN.  
 */  
void sha1_write( SHA1_CONTEXT *hd, unsigned char *inbuf, size_t inlen)  
{  
    if( hd->count == 64 ) { /* flush the buffer */  
        transform( hd, hd->buf );  
        hd->count = 0;  
        hd->nblocks++;  
    }  
    if( !inbuf )  
        return;  
    if( hd->count ) {  
        for( ; inlen && hd->count < 64; inlen-- )  
            hd->buf[hd->count++] = *inbuf++;  
        sha1_write( hd, NULL, 0 );  
        if( !inlen )  
            return;  
    }  
  
    while( inlen >= 64 ) {  
        transform( hd, inbuf );  
        hd->count = 0;  
        hd->nblocks++;  
        inlen -= 64;  
        inbuf += 64;  
    }  
    for( ; inlen && hd->count < 64; inlen-- )  
        hd->buf[hd->count++] = *inbuf++;  
}  
  
  
/* The routine final terminates the computation and  
 * returns the digest.  
 * The handle is prepared for a new cycle, but adding bytes to the  
 * handle will the destroy the returned buffer.  
 * Returns: 20 bytes representing the digest.  
 */  
  
void sha1_final(SHA1_CONTEXT *hd)  
{  
    u32 t, msb, lsb;  
    unsigned char *p;  
  
    sha1_write(hd, NULL, 0); /* flush */;  
  
    t = hd->nblocks;  
    /* multiply by 64 to make a byte count */  
    lsb = t << 6;  
    msb = t >> 26;  
    /* add the count */  
    t = lsb;  
    if( (lsb += hd->count) < t )  
        msb++;  
    /* multiply by 8 to make a bit count */  
    t = lsb;  
    lsb <<= 3;  
    msb <<= 3;  
    msb |= t >> 29;  
  
    if( hd->count < 56 ) { /* enough room */  
        hd->buf[hd->count++] = 0x80; /* pad */  
        while( hd->count < 56 )  
            hd->buf[hd->count++] = 0;  /* pad */  
    }  
    else { /* need one extra block */  
        hd->buf[hd->count++] = 0x80; /* pad character */  
        while( hd->count < 64 )  
            hd->buf[hd->count++] = 0;  
        sha1_write(hd, NULL, 0);  /* flush */;  
        memset(hd->buf, 0, 56 ); /* fill next block with zeroes */  
    }  
    /* append the 64 bit count */  
    hd->buf[56] = msb >> 24;  
    hd->buf[57] = msb >> 16;  
    hd->buf[58] = msb >>  8;  
    hd->buf[59] = msb       ;  
    hd->buf[60] = lsb >> 24;  
    hd->buf[61] = lsb >> 16;  
    hd->buf[62] = lsb >>  8;  
    hd->buf[63] = lsb       ;  
    transform( hd, hd->buf );  
  
    p = hd->buf;  
#ifdef BIG_ENDIAN_HOST  
#define X(a) do { *(u32*)p = hd->h##a ; p += 4; } while(0)  
#else /* little endian */  
#define X(a) do { *p++ = hd->h##a >> 24; *p++ = hd->h##a >> 16; \
        *p++ = hd->h##a >> 8; *p++ = hd->h##a; } while(0)  
#endif  
    X(0);  
    X(1);  
    X(2);  
    X(3);  
    X(4);  
#undef X  
}  
  
/* 
int main (int argc, char **argv)  
{  
    assert (sizeof (u32) == 4);  
  
    if (argc < 2)  
    {  
        fprintf (stderr, "usage: sha1sum string\n");  
        exit (1);  
    }  

    SHA1_CONTEXT ctx;  
    int i;
    unsigned int val = 0;  
    sha1_init (&ctx);  
    sha1_write(&ctx, (unsigned char *)argv[1], strlen(argv[1]));
    sha1_final (&ctx);  
    for (i=0; i < 20; i++)  
        printf ("%02x", ctx.buf[i]);  
    printf ("  %s\n", argv[1]);  
    for (i=0; i < 20; i++)  
	val = (val << 5) + val + ctx.buf[i];
    printf ("%u", val);  
    return 0;  
} 
*/
